When programming graphics applications, one of the more frustrating aspects of development is that you can end up writing thousands of lines of code and when you run it, all you get is a blank screen. Or maybe a blue screen. Or a crash. But often, not actually a useful image. Errors in state setting, transformation math, and other coding problems can mean your application is completely valid just not useful. Other kinds of coding problems are due to misuse or abuse of the Direct3D API itself. In those cases, enabling the 'debug' device can quickly help identify the problems.--- End quote ---